Metadata has been associated with digital images, and is typically supported by online photosharing sites. However, digital image metadata has shared the same restrictions as metadata in general. It has been limited to standard metadata as defined by the various versions of the Exif standard. This metadata is of limited use to most users of digital images. Some cameras produce proprietary metadata, however, specialized PC software is required to parse, interpret, and store the image metadata. Some photo hosting sites support the specification of a limited amount of metadata. This metadata is restricted in that users cannot define new metadata fields or are limited to a fixed number of “user defined” fields. The ability to provide optional “user defined” metadata may be provided, but is limited because metadata support usually does not extend much beyond that defined by the Exif image file format standard. In addition, the methods the photoshosting sites use to store and transmit the metadata is propriety, making its use beyond that of the photohosting site limited. Further, searches are usually limited to only a subset of the limited metadata that is supported by a site.
It is expected that camera manufacturers and photohosting sites will soon begin storing the metadata they support in XML or RDF (Resource Description Framework) format. This will go along way towards making this metadata useful to a large range of applications. RDF, developed by the World-Wide Web Consortium (W3C), provides a schema language for defining metadata vocabularies that allows interoperability between applications that exchange metadata. RDF allows descriptions of Web resources, which is any object with a uniform resource identifier (URI) as its address, to be made available in machine readable form. RDF is an application of XML and extends the XML model and syntax to be specific for describing resources. A resource is can be anything which can be uniquely identified. That is anything which can be assigned a URI. RDF supports a class system where a class specifies a set of properties and constraints on the possible values of those properties. These classes are specified using a schemal language, such as RDF Schema. A collection of property values associated with one or more of these classes is called an RDF description. Each of these properties has a property type and value specified in the associated schema. Schemas are identified uniquely by assigning each a URI. RDF utilizes the namespace facility of XML to point to a URI. Thus, the schema can be accessed at the URI identified by the namespace.
Even though RDF enables metadata to be understandable to many applications and enables metadata to be infinitely extendable, the use of metadata by photosharing sites would still be problematic. The primary problem is that a user wishing to use these capabilities must understand the technical details of RDF to define his/her metadata.
One problem with RDF, however, is that the syntax is complicated to learn, especially for a non-computer user. For instance, the following is a portion of the RDF syntax for describing a report:
<Description about = “http://flashpoint.com./report.html”><DC:Title> Specifying and Assigning Metadata </DC:Title><DC:Creator> Paul Morris </DC:Creator><DC:Date> 2001-01-01 </DC:Date><DC:Subject> Metadata, RDF </DC:Subject></Description></RDF>Thus, users will not be able to specify metadata to suit his/her own particular needs without becoming an expert in RDF and XML. Further, even if the user took the time to learn RDF and XML, there is currently no mechanism to support for the storage, display, management, or use of this “user defined” metadata.
Accordingly, what is needed is a system that allows a user to specify metadata for digital files that suits the user's own particular needs, provides storage/retrieval for this metadata, and integrates this metadata into its service, such as image presentation, searching, and grouping. Further, the system must enable this without requiring the user to understand the underlying technologies associated with the metadata schema and specification languages. The present invention addresses such needs.